Conventionally, there has been known a test chip for use in DNA analysis, biochemical tests and the like, as disclosed in patent literature 1. As shown in FIGS. 12A and 12B, the test chip is provided with a chip body 110 in the form of a flat plate, a reservoir part 112 for storing a test solution such as a reagent, and a reaction part 114 for reacting the test solution stored in the reservoir part 112 with a sample or the like. The reservoir part 112 is provided with reservoir concave parts 112a, and a seal member 112b in the form of a sheet. The reservoir concave parts 112a are formed in the upper surface of the chip body 110, and are recessed downwardly. The seal member 112b is attached to the upper surface of the chip body 110 in such a manner as to cover the upper openings of the reservoir concave parts 112a in a state that a test solution is stored in the reservoir concave parts 112a. 
In the thus-configured test chip 100, at first, a sample and the like are placed on the reaction part 114. Then, a hole is formed in the seal member 112b with use of a nozzle member 116 (see FIG. 12B), and the test solution in the reservoir concave parts 112a is sucked with use of the nozzle member 116. The sucked test solution is ejected onto the reaction part 114, on which the sample is placed, with use of the nozzle member 116. By the above operation, the sample and the test solution are mixed and reacted with each other. Then, a test result is obtained based on the reaction.
The seal member 112b of the test chip 100 is a member for use in preventing vaporization of the test solution from the reservoir concave parts 112a and intrusion of foreign matter into the test solution until the sample is tested with use of the test chip 100. Therefore, it is unknown whether adhesion (sealability) between the nozzle member 116 and the seal member 112b is sufficiently obtained during a period of time when the nozzle member 116 is inserted through the seal member 112b for injecting or sucking the test solution in and out of the reservoir concave parts 112a. In view of the above, liquid leakage from between the nozzle member 116 and the seal member 112b should be taken into consideration, when the inner pressure of the reservoir concave parts 112a is greatly fluctuated during an operation of sucking and injecting the test solution in and out of the reservoir concave parts 112a with use of the nozzle member 116 inserted through the seal member 112b. 
As disclosed in patent literature 2, there is known a seal member for use in sealing a straw insertion hole of a paper beverage container, as a seal member taking into consideration of adhesion between a nozzle member and the seal member when the nozzle member is inserted through the seal member, for instance. As shown in FIG. 13, the seal member is configured such that an insertion hole periphery 210 of a straw insertion hole 211 of a paper beverage container is held between an inner film 212 disposed on the inner side of the insertion hole periphery 210, and an outer film 214 disposed on the outer side of the insertion hole periphery 210. In this state, portions of the inner film 212 and the outer film 214 corresponding to the straw insertion hole 211 are adhered to each other by thermal adhesion. The outer film 214 is a polymer film. The inner film 212 is formed by laminating an aluminum sheet 216 and a polymer film 218 one over the other by thermal adhesion.
In the thus configured seal member 200, when a straw is inserted into the paper beverage container through the seal member 200 via the straw insertion hole 211 by pressing a sharp end of the straw against the seal member 200, adhesion is secured between the outer circumferential surface of the straw and a periphery of the opening (opening formed by inserting the straw) of the seal member 200. Thus, there is no likelihood that the contents (beverage) in the paper beverage container may leak from between the outer circumferential surface of the straw and the opening periphery of the seal member 200.
However, since the films 214, 216, and 218 constituting the seal member 200 are adhered to each other by thermal adhesion, the adhesion force between the films 214, 216, and 218 is weak. Accordingly, if the inner pressure fluctuation of the paper beverage container is repeated, or an operation of inserting and taking out a straw is repeated, the films 214, 216, and 218 may be peeled off from the opening periphery of the seal member 200. This peeling-off phenomenon gradually spreads. If the peeling-off phenomenon of the films 214, 216, and 218 constituting the seal member 200 spreads as described above, liquid leakage may occur from the peeled portions. As a result, even if the seal member 200 of the paper beverage container is used to seal the fluid channel or the reservoir concave parts of the test chip 100, liquid leakage may occur by pealing off of the films from each other, as the inner pressure of the fluid channel is fluctuated by sucking and injecting a test solution with use of a nozzle member inserted through the seal member 200, or as the operation of inserting and taking out a nozzle member with respect to the seal member 200 is repeated for sucking and injecting a test solution.